New Lightwave Modulator

It was installed on the lightbox, right beside the original 556 CW beacon / tone generator.
The crystal-controlled oscillator uses a CD4060 IC as an oscillator-divider and produces a ~550Hz or a ~1098Hz squarewave from the 4.5MHz crystal.
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4500KHz xtal divided by 8192 showing 549Hz output |
As can be seen by comparing the two oscillators (crystal on the left and 556 on the right), the 556 has a lot of drift (although it looks like it might eventually stabilize) and, as well, produces several spurious signals ... probably robbing power from the main tone. The crystal-controlled signal is rock solid and doesn't appear to generate any parasitic signals in the process. The trace below the crystal signal is unrelated to the oscillator.
When I first wired the unit up, I found an unstable low frequency oscillation from the 4060 during key-up conditions, due no doubt, to the lengthy leads inside the box. This was cured by adding a pull-up resistor to the keying line as shown in the final schematic below.
Now it's on to building another fresnel-lens receiver box which will be needed for any field work here on the island.
Can you suggest a source for parts?
73 /paul W3FIS
Paul …. my first choice is always Digikey because of their inexpensive fast shipping. Second choice is Mouser.
Steve
Paul: Have you tried modulating the light with RF? Maybe 500 kHz. Use cw, and a sensitive receiver on the other end? Might be easier to copy, as it would eliminate all the hum and other light modulation you may be hearing. –Mike, WV2ZOW